None of those answers really fit the way I do my boat for winter. I drain the fresh water tank and blow out the lines. Then I put a heater in the engine room and 5 heaters throughout the cabin areas.
We usually do our last cruise of the year for the Christmas Lighted Boat Parade and the first cruise has always been on New Year's Day. This year we'll be in AZ from the end of December until end of February so our first cruise will be some time in March.
I would consider cruising in December and again on January 1 to be a year round cruiser.